Thanks everyone. I've learned a LOT in the last few days. I've been playing with MotorCalc to aid in prop selection.

Performance seems to be good with the 10x4.7 prop. I flew for about 15 min yesterday and about 20 min today and had a great time. I've been flying on soccer fields at my university.

It's nerve-wracking to fly with a LiPoly battery and a GWS speed control because it won't cut the motor until the battery is below 6v unloaded. (Guess how I know this?) I hope my experimentation has not harmed my battery. I flew for a long time today and could have flown more but I was getting nervous about the voltage. So I brought it home and put it on the multimeter -- battery was still reading 7.2 volts. Cool.

Incidentally, the reason I did all this was because I read somewhere that it is a good idea to test your setup on the ground to see how much flight time you can expect. Thanks to everyone here, I now know that to be bad advice.

As soon as I can get my hands on the proper adapter, I'm going to try flying with a 9x6 prop. I expect to lose some thrust but gain some speed. It's a HD prop and has a 4mm hole rather than a 3mm hole so I'm going to have to get an adapter for it.

Oh, according to MotorCalc, the 10x8 prop will draw 10.5 amps, so I probably won't be using it until the KAN 650's I ordered come in. MotorCalc says that the prop will be stalled. What does this mean as far as flight characteristics are concerned? Less efficiency?